What happened
On July 29, 2010, at 20:06 UTC, a Piper PA-34, registration PT-KGK, was performing a navigation training flight from Jacarepaguá Airport (SBJR) to Campo de Marte (SBMT). The crew, consisting of an instructor and a student pilot, was operating under visual flight rules in favorable meteorological conditions.
During the final approach to Campo de Marte, the left engine began to malfunction. Although the pilot maintained control of the aircraft and successfully touched down on the runway, the left engine subsequently ceased operation while the aircraft was taxiing. The impact and subsequent engine failure resulted in substantial damage to the aircraft. Both occupants of the aircraft were unharmed.
The investigation
CENIPA investigators examined the left engine to determine the cause of the failure. Upon opening the engine, investigators discovered significant internal damage within cylinder number 2. The findings included broken intake and exhaust valve springs, a broken intake valve tappet, and a deformed rocker arm shaft. Additionally, metal shavings and fragments were found inside the oil sump and cylinder number 2.
Review of the aircraft's maintenance logs showed that all periodic maintenance services had been performed in accordance with the manufacturer's manual. There were no records of recent corrective maintenance interventions on the affected engine. Based on the evidence, investigators determined that the mechanical failure was likely caused by material fatigue.
Findings
- Material fatigue of one or more valve springs, which subsequently triggered the failure of the valve train components.
- The failure of the left engine occurred during the final approach and continued through the taxi phase.